The present invention relates to a system for piloting an electric motor in electric motorcycles or the like.
The use is well known and increasingly more common of motorcycles with electric propulsion.
The electric motorcycles of known type comprise an electric motor, normally made up of a single-phase alternating current motor or of a brushless motor, a rechargeable electric battery and an inverter connected to the electric battery and able to control the electric motor.
In practice, the inverter receives a signal from the throttle knob of the electric motorcycle, and converts this received signal into a corresponding supply current/voltage of the electric motor.
Furthermore, during this phase of power delivery to the electric motor, the inverter takes a predetermined current from the electric battery and appropriately converts it into power supplied to the electric motor.
Furthermore, electric motorcycles of the known type may have a regenerating system, i.e., a system able to recover energy during slowing down/braking of the motorcycle in order to use it to recharge the electric battery.
Consequently, during slowing down and/or braking the recovered energy translates into a current sent to the electric battery of the motorcycle, to recharge the battery itself.
The electric propulsion systems of known type do however require a number of devices.
It can occur in fact that the current required from the inverter to the electric battery, determined according to the signal received from the throttle knob, exceeds a preset maximum value of the current deliverable at output, with consequent malfunction of the electric propulsion system, or even, in some cases, damage to the battery itself.
Similarly, during braking, the current sent to the electric battery may exceed a maximum preset value of charging current at input.
In order to prevent this drawback, the use is known on electric motorcycles of BMS (Battery Monitoring System) electronic systems to manage the rechargeable batteries.
In particular, such BMS systems are used to carry out a continuous monitoring of the state of the battery and to keep the battery within the so-called Safe Operating Area (SOA), i.e., within those current and voltage operating conditions such as to avoid any risk of damage.
In general, the BMS systems of known type permit monitoring the battery operating parameters such as voltage, output or input current, temperature, charge level and, furthermore, are able to perform the dynamic calculation of the maximum permissible current charge values at input and of delivered current at output.
The overcurrent protection (both during charging and during the delivery of current) is commonly effected by means of an internal switch able to be operated and then opened by the BMS system in the event of a current exceeding the maximum allowed value being detected.
Furthermore, an appropriate signal can be sent to the devices connected to the battery, so as to require a limitation or interruption of the use of the battery.
The use of the BMS systems of known type, however, entails some drawbacks.
In particular, the protection of the battery is operated ‘a posteriori’, i.e., only once the BMS system has detected the presence of overcurrent, and is done by means of sudden limitations of the current delivered by the electric battery, or even, by means of interruption of the battery connection itself.
This results in an inconvenience and greater riding difficulty for the user who, besides receiving and having to manage the warning messages displayed on the motorcycle monitor, is forced in many cases to recharge the battery within a very short time.